Polymerizable compositions are useful components in a number of applications and products and can be used, for example, as an adhesive, a coating, a sealant, a molding, a film, or as a composite binder. Known polymerizable compositions, however, have suffered from the need to use external polymerization initiators to initiate polymerization. Such use of polymerization initiators, however, has a number of drawbacks. For example, polymerization initiators cannot be removed after polymerization and remain in the cured composition affecting various attributes of the cured composition. Additionally, systems with external polymerization initiators are difficult to control. It would therefore be advantageous to provide a polymerizable system that can be easily cured on a variety of substrates without the addition of a polymerization initiator while retaining excellent mechanical properties.